sortix--sortix/libc/string/explicit_bzero.c

/*
 * Copyright (c) 2011, 2012, 2014 Jonas 'Sortie' Termansen.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 *
 * string/explicit_bzero.c
 * Initializes a region of memory to a byte value in a manner that is not
 * optimized away by the compiler.
 */

#include <string.h>

// TODO: Employ special compiler support to ensure this is not optimized away.
void explicit_bzero(void* dest_ptr, size_t size)
{
	volatile unsigned char* dest = (volatile unsigned char*) dest_ptr;
	for ( size_t i = 0; i < size; i++ )
		dest[i] = 0;
}